The increasing demand for electric power over the last decade has urged the high voltage apparatus to operate at full load while the power systems are expected to provide high quality and reliable electric power. On the other hand, the increasing dependence on the electricity has increased the cost of power outages and quality disturbances. In order to avoid power outages and disturbances caused by equipment failures and outages, online distributed and low-cost condition monitoring, diagnostics and protections are crucial in modern power systems.
Electric field measurement in the vicinity of high voltage apparatus is part of condition monitoring and protection in power systems. Determining the electric-field distribution profile surrounding a high voltage equipment provides reliability information about the insulation condition.
Most recent efforts in the development of electric field measurement sensors have been towards optical sensors. These sensors convert electrical signals to optical signals based on the Pockels or piezoelectric effects. The most significant advantage of these sensors is that they do not require any contact to the high voltage apparatus, which makes them portable measurement devices and also eliminates the source loading and power dissipation. Further, the all-fiber structure of these sensors minimizes the risk of flash over and provides electric isolation from the high voltage apparatus. Although these sensors are considered portable measurement devices, the weight of the optical voltage measurement structures known as optical voltage transducers is considerably high. The information received from these sensors is transmitted by optical rays through fiber optic cables. They are considered as active sensors which require external source of power and safety precautions for installation. Accordingly, systems and methods that enable measurement of high voltage AC electric fields remains highly desirable.
It will be noted that throughout the appended drawings, like features are identified by like reference numerals.